QUAriTri'AT:CVE GHAI'jGES 111 VARIOUS SUGAR GOIjCm'RATlOKS UJRIMG FEH'IiSm'ATlOII Oi<' DOUGliS, SPONGiiS AMD BRliT/ZS ^' Ting Jui Tan^ 3. S., Tai-.v-an Provincial ChTJungshing Universitj . A MSTEK'S THESIS subnitted in partial fulfilLTient of the req-uireiaent Tor the decree MSTitlR OF SCIENCE Food Science Depairtinsnt Ox Grain Science arid Ladiistiy KAIIS'IS STATK UNXVilRSI'i'Y Manhattan, Kansas 1963 ApTrov'i'id by: I'lajor Professor . ' - LD . /?(? . tSX table of coiitehts eitroduction 1 REVIEV7 OF LITER/iTUPJi; 2 I. The Carbohydrates of Ivlieat and VJheat Flour 2 II. Quantitative Determination of Sugars in Natural ............ Materials 5 III, The Fate of Sugars in Breadmaking ......... 11 ^lETHOD AND MATERIALS l6 I. Flour Samples l6 II. Formulation, Dough I-Iake-up and Balcing 16 III, Determination of Gas Production Rates 19 IV. Schedule of Sample Collection for Sugar Analyses ..... 20 V. Method of Ejctraction of Sugars from Dough, Brew, Sponge and Bread Crumb . , 21 VI. tiethods of Analyses , 21 RESULTS AND DISCUSSION 25 I. of Discussion the Experimental Methods , 25 II. Change in Total Reducing Sugars of the Extracts 31 III. Change of Concentration of Individual Sugars During Fermentation ........... ....... 32 IV. Rate of Gas Production 34 V. Residual Sugars in Bread 36 SU>2^SIRY AND CONCLUSION 37 ACKI^Oi-niEDGEMEIT Zfo LITERATURE CITED , ^ i^l ii LIST _0F TABLES I. The I-Iono- and Di- saccharide Content of Flour , 3 II, Changes of Sugar Content in Steeped and Germinated Ivheat , , , , 12 III, Size of Sar.ples Used in Detenrdnation of Gas Production Hates , . 19 IV. Determination of Su^^ar Recovery by Folin-Wu i'iethod , 2? V, 2xamples of Results Obtained by In Situ DetertGination 30 iii LIST OF FIGURES 1. Standard Curve of Folin-Wu I'lethod for Reducing Sugar Determination 27A 2, Relationship Between the Quantity of Sugar per Spot and the Integrated Area Under the Curve by Direct Photonetry in Transmitted Light at 526.5 ny^ . 29A 3, Changes of Total Reducing Sugars During Fermentation of Straight and Sponge Doughs (Flour: 9008) SUA 4, Changes of Total Reducing Sugars During Fermentation of Straight and Sponge Doughs (Flour: 9003) 3IA. 5. Changes of Total Reducing Sugars During Fermentation of Liquid Brews V/ith Different Levels of Flour (Flour: 9008) .... 313 6. Changes of Total Reducing Sugars During Fermentation of Liquid Brews V/ith Different Levels of Flour (Flour: 9003) «... 31B 7. Changes of Sugar Concentrations During Fenaentation of Straight Dough (Flour: 9008) 33^ 8. Changes of Sugar Concentrations During Fermentation of Straight Dough (Flour: 9003) 33A 9. Changes of Sugar Concentrations During Fermentation of Seventy-five (75) Percent Flour Sponge Dough (Flour: 9008) , , , 33B 10. Changes of Sugar Concentrations During Fermentation of Seventy-five (75) Percent Flour Sponge Dough (Flour: 9003) . , . 33B 11. Changes of Sugar Concentrations During Fermentation of Fifty (50) Percent Flour Brew and Dough (Flour: 9008) 33C 12. Changes of Sugar Concentrations During Fermentation of Fifty (50) Percent Flour Brew and Dough (Flour: 9003) 33C iv 13, Changes of Sugar Concentrations During Fermentation of Twenty-five (25) Percent Flour Brew and Dough (Flour: 9008) . 33D 1^. Changes of Sugar Concentration During Fermentation of Twenty-five (25) Percent Flour Brew and Dough (Flour: 9003) . 33D 15. Changes of Sugar Concentrations During Fermentation of No-Flour Brevr and Dough (Flour: 9008) ... 33E 16, Changes of Sugar Concentrations During Fermentation of No-Flour Brew and Dough (Flour: 9003) , , 33E 17, Changes in the Rates of Gas Production During the Fomentation of Straight and Sponge Doughs (Flour: 9008) . ; 35A 18, Changes in the Hates of Gas Production During the Fermentation of Straight and Sponge Doughs (Flour: 9003) . , . , 35A 19. Changes in the ?.ates of Gas Production During the Fermentation of Liquid Brews and Doughs (Flour: 9008) ..... 35B 20. Changes in the Rates of Gas Production During the Fermentation of Liquid Brews and Doughs (Flour: 9003) ..... 35B 21. Residue Sugars in Crumb of Breads I-Iade by Different Procedures on the Same General Formula (Flour: 9008) 36A 22. Residue Sugars in Crumb of Breads Made by Different Procedures on the Same General Formula (Flour: 9003) ...... 36A. EiTRODUCTIOH Yeast-leavened wheat bread has been one of the most iaiportant foods of mankind for centuries. However, it was not until the second half of 19th century that scientific investigation on the nature of yeast fer- mentation was conducted. Extensive research work concerning the nature of yeast fermentation has revealed most of the chemical mechanisms involved. Most of the earlly knowledge of yeast physiology and fermentation was obtained in nutrient solutions rather than in bread dough. The first study of the changes in concentration of various sugars in a fermenting dough was repo2rted by Koch et al. (53) in 195^. They used an analytical method developed by Dubois et al. (27), in which sugar mixtures were separated by paper chromatography and quantitatively determined by phenol- sulfuric acid method. Using the same technique, lae ct al, (6?) studied sugar changes in fermenting sponges and doughs. Recently, Lee and Chen (63) and Lee and Liao (6^) studied the change of some sugars in a fermenting straight dough by use of radioactive sucrose-"'"^C, However, limited studies concerning the fate of various sugars during continuous breadmaking processes have been reported. It was the objective of this research project to study the following: 1) The changes in concentration of various sugars during fermentation of straight doughs, sponges and brews with different levels of flour content. 2) The rate of fermentation of the straight doughs, sponges and brews, 3) The residual sugars in the bread crumb of breads made by different procedures. 2 h) The techniques necessaiy to develop simplified methods for routine , analysis of sugars in doughs, sponges, brews and bread crumb, * RBVIEi': _0F LITERATURE I, The Carbohydrates of 1'h.eB.t and Wheat Floxu:* The total carbohydrate content of wheat varies i-iith variety, weather, soil and other factors, but usually falls in the range of 63 to 73/^ (on l^Jo moisture basis) (5, 50, 51). A large percentage of the carbo- hydrate is starch, and simple sugars are present only in trace amounts, Vhe&t starch, which comprises from 5"^ to of the dry weight of whole grain and 95.8"^ of total carbohydrate of the endosperm, occxirs in granules in endosperm cells (5, 30, 35, 73). A large percentage of the wheat starch granules range in size from less than 2 to 35/* in diameter, while the largest ones range in about 50/^(99, 107, 127). Generally, m.ost of these granules are either less than 7>^JJ- or greater than l^.SyUin diameter. The small granules are sperical in shape, . average 81. 6^^ of total granule number but only ^.ifa of total vreight. The larger ones are lenticular in shape and average 12.5'p of total number of 935^ by weight (ill). VJheat starch is composed of at least txjo fractions: the unbranched airylose and branched artylopectin (101). The ratio of these two fractions varies, and the airylose fraction ranges between 17 and 2$'} (24). Some starch granules are severed during the milling operations and these "damaged" starch granules swell and gelatinize much more rapidly than the intact granules. They are readily hydrolyzed to maltose and other malto-oligosaccharides by the combined action of o(- 3 and £nr,'-lases. Since the enzymatic activity of the sound floiir is more or less constant, therefore, the rate of sugar foririation during and after dough-ni:d.ng is in proportion to the percentage of the damaged starch granules present in flour (^8), Indirectly, the octent of starch damage affects fermentation rate and also the quality of bread (56), The presence of a small amount of sucrose, maltose, fructose, glucose and raffinoso have been reported in floiu- by a number of workers (6, 11, 52, 57 y 83, 132), Positive identification and quantitative deterrirination of these sugars have been reported only recently with various chromatographic methods (29, ^0, 55» 77, 113, 13^). There appears to be soir^ lack of agreement in the results reported by different workers. This is at least partly due to the existence of great variations in variety and condition of the x>?heat studied and the methods of determination employed by the different workers. The mono- and di- saccharides contents, as reported by different workers, are sumraarized in TABLE I. TABLE I: The Mono- and Di- saccharides Content of Flour' Sugar Flour Hard Bed Darum English German Kara Red Amber Spring I'.^heat VJheat Spring Durum Glucose 0.01-0,09 0.02-C.O^ 0.09 0.06 0.03 Fructose 0.02-0.08 0.04-0.09 0.06 0.08 Sucrose 0.19-0.26 0.26-0.57 0.84 0.88 0.54 0.74 Kaltose 0.06-0.10 0.10-0.15 trace 0.04 0.05 0,18 Galactose 0.02 0.02 Data Source 125 125 77 121 72 80 "Percent of flour. Galactose was found, in wheat flour by some workers, and probably arose from the hydrolysis of galactosyl glycorides and/or raffinose during storage (72, 80). Cther disaccharides reported to be found in vjheat flours are melibiose and difructose (28, 9^). They are probably the products of partial hydrolysis of raffinose and some glucofructans. Raffinose has been known to exist in wheat for a long time (6). It exists mainly in the germ and represents 37 #6^ to ^5.3/^ of the total sugar of gem, while the remainder is mostly sucrose (28, 35» 70). The level of raffinose in flour was reported betx^een 0.19 and 0.68'^ (77, 80, 121).